1. Field of the Invention
The invention relates to emergency lighting, and particularly to fluorescent lighting wherein a ballast for a fluorescent lamp is connected to a source of electrical energy other than normal AC line current in the event that the normal AC current fails.
Emergency lighting is required in commercial, industrial, and institutional buildings just as fire extinguishers, smoke alarms and other safety equipment. Three types of emergency lighting are common in such installations: unit equipment, engine generators and central battery systems. Unit equipment falls into two principle types: fluorescent and incandescent.
The fluorescent units are customarily combined with and within a conventional fluorescent lighting unit by merely adding the emergency ballast consisting of a battery, a battery charger, inverter and sensing circuitry adjacent the standard fluorescent ballast. The sensing circuit observes the interruption of normal AC power to the lamp unit and immediately switches on the emergency ballast which powers the light fixture for the required period which, under most state safety codes, is a period of at least ninety (90) minutes, a standard called out in the National Electrical Code, NFPA Article 70, and NFPA Article 101 Life Safety Code. These regulations at NFPA, Article 101, Section 5-9.3 also mandate that periodic monitoring of the ready status of the emergency systems, including a 30 day test requiring 30 seconds of lighting and annual test requiring a 90 minute duration of lighting. An exception is provided for those emergency lighting units which contain a selftesting/self-diagnostic circuit which automatically performs a minimum 30 second test and diagnostic routine at least once every 30 days and indicates failures by a status indicator. U.S. Pat. No. 5,666,029 assigned to the assignee of the present invention is illustrative of such a self testing/self diagnostic circuit.
2. General Background of the Invention
U.S. Pat. No. 5,004,953 entitled Emergency Lighting Ballast for Compact Fluorescent Lamps with Integral Starters, assigned to the assignee of the present invention is illustrative of the fluorescent type of emergency lighting with a ballast. It is common in the installation of emergency fluorescent lighting that an emergency ballast is added to a conventional fluorescent fixture either in original installation or by retrofit. Alternatively, emergency lighting may be provided integrally in a unit having both internal regular and emergency ballasts installed. When main AC power to the lighting fails, voltage sensing circuitry instantly connects DC current from a battery (in the emergency ballast) to an inverter which produces high frequency, high voltage power to illuminate the emergency fluorescent lamp(s) for the required period.
The inclusion of test circuits for emergency fluorescent lighting is common, typically including the Test/Monitor panel, either mounted on a wall in the building, generally adjacent the emergency lamp, or on the case of the fluorescent ballast or fixture. The operation of these types of testing circuits requires the technician to go to the particular location of the test switch for each emergency fixture, which is somewhat time consuming. Such a configuration involves considerable installation cost in that the wall mounted test switch must be wired directly to each fixture to be tested. In the case of test switches located directly on a fixture, though avoiding the extra installation cost of the wall mounted switch, the technician then has to access each fixture individually to initiate the test. This procedure is time consuming since fixtures are often eight to twenty feet above the floor in commercial or industrial buildings.
U.S. Pat. No. 5,666,029 entitled Fluorescent Emergency Ballast Self Test Circuit, assigned to the assignee of the present invention is illustrative of a fluorescent emergency lighting ballast which includes an integral self test function. In the described ballast, the testing is a programmed function, carried out independently by the circuitry in the ballast and in the event of a malfunction in the test, a warning light and/or alarm sounds to advise of the test malfunction.
The present invention in its most common form involves the combination of the concept of a type of remote control as utilized with garage door openers, television and VCR machines which activates a specialized monitor circuit integrally connected into the emergency ballast for the fluorescent emergency lamp. With this remote control test feature, a technician performing the tests, whether the 30 second or the 90 minute variety, may conduct a survey of several emergency fixtures in a xe2x80x9cpoint-click-testxe2x80x9d series while making a tour through a facility, returning within the required time frame (30 seconds or 90 minutes) to observe that the lamp is still operating in the emergency mode and meeting the requirements of the Life Safety Code. In a preferred embodiment, the test unit includes a reset function to terminate any unwanted prior test activation. On reset, any prior test of the emergency ballast to emergency (i.e., battery) function is terminated and the lamp is reconnected to normal AC power, with the battery charging circuit also energized.
Prior attempts of providing fluorescent emergency lighting with such remote control operation have been unsuccessful. The significant amounts of infrared light (noise) produced by fluorescent lamps interferes with conventional remote control transmitters and receivers, to the degree that reliable, repeatable tests have not been possible. Further, the significant amount of infrared noise within the fluorescent fixture has prevented the mounting of a useful detector of the remote test control signal. The present invention breaks through the infrared noise barrier by using a uniquely coded signal which interrogates the fixture and if analyzed to be of a proper digital pulse train, and upon successful match, initiates the particular requested test sequence (30 second or 90 minute). The invention further provides a novel infrared detector housing further enhancing the receipt of the coded signal and novel cabling to connect the detector to the control circuit in the emergency ballast.
It is an object of the present invention to perform selective testing of an emergency ballast of a fluorescent luminaire.
A collateral object of the invention is to perform testing in the emergency ballast which closely simulates the emergency function of the luminaire, verifying that the emergency capacity of the luminaire is functional.
A further object of the invention is to provide for remote activation of the emergency test without having to activate a test switch located on the luminaire or at a discrete location.
These and other objects of the present invention are achieved by a lighting system including a luminaire including a fluorescent lamp, means for delivering main AC power to the lamp from an AC power source; a DC power source consisting of a stored energy supply; rectifier means for recharging the stored energy supply; inverter means connected to the stored energy supply for producing power from current provided by the DC power supply; supplying such power to the lamp when the mains AC power is interrupted and means for deactivating the inverter when main AC power is being supplied to the lamp; a remote infrared transmitter capable of emitting a coded signal for interrogating an emergency ballast test control; an infrared detector coupled to a microcontroller through a quick connect shielded cable to receive, examine and decode the coded signal, the microcontroller signaling the emergency ballast to supply power from the stored energy source by switching off the mains AC power upon recognition of the coded test signal.